I don't don't know beans about horses, but I ran across the SFJ in the library and thought I'd pass it on. I guess if you had a clean river or a big pond/lake it water would not be a problem. With horses you have no worrys about gas or electicity at least.
I think for some folks lucky enough to have a retreat/farm it might make sense to have a few horses, if you had good wells and capacity to grow enough feed. If we have a total meltdown of society, you could still have your horses. Buy now, while the markets is depressed